1. Field of the Invention
The present invention relates to a technique for performing a route setting in an optical wavelength division multiplexing (WDM) transmission.
2. Description of the Related Art
FIG. 22 is a diagram showing a configuration of an optical wavelength division multiplexing transmission system, which has a WDM transmission network, an optical transmitter, an optical receiver, and a network controller. The optical transmitter sorts transmission signals inputted from a transmitting terminal into respective wavelength components. The sorted transmission signals (electrical signals) are converted into respective optical signals, wavelength-multiplexed, and sent to the WDM transmission network. The optical receiver receives the optical signals transmitted through the WDM transmission network, converts the optical signals into the electrical signals, and transmits the electrical signals to a receiving terminal. The network controller has a management function for the WDM transmission network, the optical transmitter, the optical receiver, and the like. The WDM transmission network has a plurality of NEs (Network Elements) which are connected in a mesh manner and repeat the transmission signals.
In the wavelength division multiplexing transmission system as shown in FIG. 22, when a new line is added, a transmission property of the transmission signals of each route in the WDM transmission network is evaluated, and the optimal route for each wavelength component of the transmission signals in the WDM transmission network is retrieved and set.
As the prior art related to this invention, for example, there is a wavelength division multiplexing transmission system as disclosed in Patent Document 1.
[Patent Document 1] JP-A 2002-26822
Patent Document 1 proposes a method of retrieving the optimal route for each wavelength component and setting the route. However, in a case where the route can be selected only for each wavelength component, there is a possibility that it is caused a problem that a route must be determined so as to bypass the optimal route such as shortest route.
Also, in a case of avoiding the foregoing problem, it is necessary to switch a wavelength currently used to a different wavelength. Thus, there is a possibility that influence is given to lines under operation.
Also, a portion between a start point and an end point of the optimal route in the WDM transmission network does not always have the same wavelength. In the optimal route, the wavelength is also considered to be different between the NEs.
Moreover, since the new line is added to the optimal route, the influence (OSNR (Optical Signal to Noise Ratio) degradation, deterioration in gain tilt, and the like) is inevitably given to the other lines, but the measure against it is not considered.